“She is a world-class bowler who has performed over a long period of time.
“To have her come in at the back end of Malaysia was a good boost for the group.
“She has done a lot of hard work to get here, it’s great to have her and it gives us options with the ball which is great.”
Jonassen’s availability will create a selection conundrum for coach Matthew Mott for Australia’s opening game against Pakistan on Saturday (AEDT).
Fellow left-arm orthodox bowler Sophie Molineux stated her claim in Kuala Lumpur, taking 13 wickets at an average of seven in three T20s and three one-day internationals against Pakistan.
Mott also has hard-hitting off-spinning all-rounder Ashleigh Gardner at his disposal, meaning teenage legspinner Georgia Wareham could be the player to miss out.
Lanning said she would have no problems overcoming a minor back concern to play in Australia’s last warm-up match against South Africa on Wednesday (AEDT) in Guyanna.
Australia will stay on the island for each of their group matches against Pakistan, Ireland, New Zealand and India, with the top two teams qualifying for the semi-finals.